In order to measure the position of a survey point or the like by using a conventional surveying instrument such as a total station (electric distance/angle meter), it was necessary to collimate a target placed at the survey point. In recent years, a surveying instrument having an automatic collimator has appeared on the market, in order to reduce the labor of an operator collimating a target. The surveying instrument having such an automatic collimator has come to include a remote control device so that a survey can be performed by a single operator. However, the surveying instrument provided with the automatic collimator has a conventional problem in the fact that a collimation telescope must scan a wide range in order to set the target within a narrow visual field of the telescope, and hence much time is consumed for automatic collimation and for the survey.
To solve the problem, an automatic tracking type surveying instrument that automatically tracks a target has also appeared on the market (see Patent Document 1 mentioned below). The conventional automatic tracking type surveying instrument is characterized in that tracking light is emitted along the collimation axis (optical axis) of a collimation telescope when a target is moved, and the direction of the target is calculated by receiving the tracking light reflected by the target while allowing the collimation telescope to always continue to be automatically directed toward the target
[Patent Document 1] Japanese Published Unexamined Patent Application No. 2004-132914